The Hall of North American Mammals reopens this month at the American Museum of Natural History in New York CIty, after a pretty thorough restoration effort that involved—among much else—replacing all of the older lighting fixtures with fixtures that are more energy efficient.

It wasn't quite so simple as swapping out a few bulbs, though, and calling it a day. At least not when it came to the wolves.

In the AMNH's wolf diorama display, changing out the lighting fixtures changing "the entire lighting balance, and some of the values," explains Senior Project Manager Stephen C. Quinn, in the video above. In other words: the shadows in the scene were not realistic to the manner in which the diorama was lighted.

To remedy this, the museum added various pigments of crushed marble dust to the faux snow in the wolf scene, to camouflage the multiple shadows created by the five new light sources. They were able to effectively erase shadow with careful shading, and recreate moon-realistic eerie blue shadows for the wolves and flora in the scene.